Official support for the YouTube app on Android 4.1.2 (Jelly Bean) has ended, as modern versions of the app now require Android 9.0 or higher
Important for Android 4.1.2:
Choose streams with container = "mp4" and encoding = "h264" for hardware decoding. youtube for android 4.1 2 uptodown
Enable Unknown Sources: Go to Settings > Security and toggle on Unknown Sources to allow installation from outside the Play Store . Official support for the YouTube app on Android 4
As he scrolled through the homepage, he noticed that the app was a bit outdated, but it still had the core features he loved. He could watch videos, create playlists, and even comment on his favorite videos. Features: Background playback, ad-blocking, black theme
Since the latest app won't install, you must download a legacy APK. Version: YouTube 10.02.3 (or older) Compatibility: Android 4.0.3+ Source: YouTube Legacy Versions on Uptodown 🛠️ How to Install
Since official YouTube app no longer supports Android 4.1.2, you would be building an alternative client using the YouTube Data API v3.